Stitch adjusting mechanism



May 26, 1959 c. J. M. BENINK ETAL 2,837,968

STITCH ADJUSTING MECHANISM Filed Oct. 2, 1957 3 Sheets-Sheet lINVEN7'0P5 May 26, 1959 c. J. M. BENlNK ET AL 2,887,968

STITCH ADJUSTING MECHANISM 3 Sheets-Sheet 2 lNVE/VTOPS w M W May 26,1959 c. J. M. BENINK ET AL I 2,887,968

STITCH ADJUSTING MECHANISM I Filed Oct. 2, 1957 3 Sheets-Sheet 3 AYWJWAGL'IVT United States Patent STITCH ADJUSTING MECHANISMApplicationOctober 2, 1957, Serial No. 687,730 Claims priority,application Germany October 9, 1956 4 Claims. (Cl. 112-210) The presentinvention relates to sewing machines and is particularly concerned withthe improvement of the stitch adjusting mechanism of the type disclosedin application Ser. No. 608,915, now Patent No. 2,844,114, to providefor controlling the length of the forward and the reverse stitcheffected by the machine automatically.

It is therefore an object of the invention to provide automatic meansfor controlling the length of forward and rearward stitches made by themachine.

It is a further object of the invention to make possible the use of theoperating lever for adjusting the stitch length also for setting of theautomatic control and setting of the magnitude of the controlled stitchlength..

In accordance with the invention a slide lever havingv a guiding slideportion and a free motion portion which is movable together with theabutment lever and a .connecting bar having a pin guided in said slidefor transmitting the guiding impulses for the stitch length from theguide cam disk are provided, which levers can be coupled with oneanother by rotating a disk arranged coaxially with the stitch settingshaft and having an elongated aperture beyond thezero position of thestitch setting device for the automatic control of the forward andreverse stitch.

Further advantages and objects of the invention will become apparentfrom the following specification describing the invention with referenceto an embodiment thereof illustrated in the accompanying drawingsinwhich:

Fig. 1 shows a front view of a sewing machine incorporating theinvention;

Fig. 2 is a section taken along line IIII in Fig. 1 drawn to an enlargedscale;

I Fig. 3 is a partial sectional view taken along line III-'- III in Fig.2 showing the position of the disk for forward stitching;

Fig. 4 is a top view partly in section taken along line IV-IV of Fig. 3;

Fig. 5 is a sectional view along line VV'in Fig. 4 showing the disk inzero position; and t Fig. 6 is a section taken along line VIVI in Fig. 4in which the disk is in position for automatically guiding the stitchsetting mechanism. a

The sewing machine in accordance with Fig. lincludes the customary baseplate 1, a standard 2 as well as arm portion 3 and a machine head 4. Thearm shaft 5 is journalled in the arm 3. A balance wheel 6 is supportedhollow shifting sleeve 31.

Patented May 26, 1959 2 feed dog advancing shaft 14 journalled in a boss13 projecting from the base plate.

A sliding member 16 is secured to the cam follower bar 11 by means of ascrew 15 and is received in the stitch setting slide 17 which ispivotally journalled by means of shaft screw 18 and sleeve 19 in thestandard 2 (Fig. 3) which is provided for this purpose with a recess 20.Anarm 21 is provided on the slide 17 to which a draw bar 23 is pivotallyconnected by means of a collar screw 22.

The feed dog raising shaft 25 is journalled in a lug 24 in the baseplate 1 which is connected in the usual manner to the dog raising cam(not shown) on the arm shaft 5 by way of a crank 26 and cam follower bar27.

A boss 28 on the front side of the standard 2 is provided with a bore inwhich a bearing sleeve 30 is mounted to receive hollow shifting shaft 31to theoutwardly projecting end of which the operating knob 32 issecured, while a sleeve 34 with the guide disk 35 is secured by means ofa screw 33 tothe inwardly extending end of shaft 31. Disk 35'is providedwith an aperture 36 (Fig. 3) presenting curves 37 and 38 for determiningthe inner and outer limits, respectively, relative to the axis ofrotation.

An oflset supporting arm 39 is fixedly secured by means of screws 40 tothe bearing sleeve 30 (Fig. 4). This arm 39 extends through the aperture41 in the housing into the standard 2. A stud 42 is provided on the freeend of arm 39 on which the abutment lever 44- is journalled by means ofa hub 43 and held in place by a lock ring 45. Lever 44 presents theabutment pin 46 (Fig. 3) which projects into the disk 35. The free endof the lever 44 is set off at an angle and is joined to the draw bar 23by means of collar screw 47 (Figs. 2 and 4). v v The stitch settingslide 17 (Fig. 2) is provided with an arm 48 having'a bore 49 which isengaged by one end of a spring 50, the other end of which is secured toa hook member 51 which engages the recess 52 in a cage 53 of thestandard '2. The spring tends to turn the slide 17 in a manner that thepin 46 of the lever 44 engages the curved edge 37 for the forward stitchin the guide disk 35.

A pin' 54 is secured to the angular end of the lever 44 (Figs. 4 and 5)which extends into the plane of the arm 55 of adjusting member 56 whichis fastened to the clamping sleeve 57 which is securely fastened bymeans of set screw 58 to the stitch setting shaft 59 journalled in theThe free end of shaft 59 is provided with a manipulating grip or lever60.

v Adjusting member 56 is biased by a spring 61 (Figs. 4 and'5') which ishooked at one end into a bore 62 of a second lever arm 63 and at theother end around a groove i 64 in the stud 42. This turns member 56counterclockwise as seen in Fig. 5 until the third lever arm 65 of theadjusting member 56 abuts the reduced end 66 of the stud 42.

For the automatic control of the forward and reverse stitching inaccordance with the invention the aperture 36 on the end of the shaft 5which projects from the housing, 9

of disk 35 is widened in a manner to permit clearance for movement ofthe abutment pin 46 on lever 44 towards the other side, so that pin 46does not touch the two limit lines of the aperture portion 36'. The disk35 is reinforced by means of a thin disk 67 secured thereto. Disks 35and 67 carry a pin 68 which is enabled during rotation of the disks 67or 35 in counterclockwise direction to enter a throat in connecting bar69 (Figs. 3

and 6) in order to thus shift the connecting bar 69 about manner by thestitch setting lever 8 provided in the arm 5 its. axis of rotation 71 tothe left as seen in Fig. 3. In this manner a pin 72 on connecting bar 69is brought into engagement with a guiding slot 73 (Fig. 6) of a guide orslide lever 74 on hub 43, thus establishing operative connection betweenconnecting bar 69 with stitch setting slide 3 17 by way of levers 23, 44and 74. Slot 73 is of the shape of a circular are having its center atthe pivot axis 71. Toward the free end of lever 74 the arcuate slot 73leads into an aperture 75 extending substantially perpendicularly tosaid slot and which constitutes the free wheeling portion of the slottedlever 74. The inner limit of the aperture 75 is defined by an arcuateedge, the center point of which is at the axis of rotation of lever 74.Fig. 3 illustrates the disengaged position of connecting bar 69 wherethe pin 72 rests against the arcuate border line of the aperture 75under the pressure of the spring 76 which is disposed around the pivotaxis 71.

The connecting bar 69 (Figs. 2, 3 and 4) is journalled at its upper endon pivot axle 71 which is secured in the lever arms of a U-shapedangular lever 77 which is journalled on a pivot axle 78 which, in turn,is secured to a bearing support 80 mounted by means of screws on thesupporting plate of the machine. One arm 81 of the angular lever 77 isconnected to one end of a guide link 82 which is twisted by a 90 angle,the other end of which is secured to the bent up arm 83 of a rockinglever 84. This rocking lever 84, in turn, is pivotally mounted by meansof a collar screw 85 and presents a further arm 86 which is alsoangularly bent and presents a follower 87 which is in engagement withthe guide cam disk 88 for controlling the forward and reverse stitchingof the machine and which is provided in a known manner in the nest ofcams 89 for the lateral deflecting of the needle bar, which cams aredriven by the arm shaft 5,

The setting of the desired stitch length is effected in a manner knownper se by rotating the control knob 32 from zero position of Fig.clockwise, which causes the abutr ment 46 to slide along the outer limitcurved edge 37 because the abutment lever 44 is biased upwardly byspring 50 by way of draw bar 23 and the stitch setting slide 17.

For setting up the corresponding reverse stitch of equal length themanual lever 60 is rotated clockwise counter the force of spring 61 asviewed in Fig. 3, until arm 55 of the adjusting member 56 presses lever44 downwardly, to a sufiicient extent to cause abutment 46 to contactthe reverse stitch guide edge 38. As the lever 60 is released theadjusting member 56 returns to its initial position under the tension ofspring 61 which brings the abutment 46 again in engagement with theforward stitch guide edge 37.

During the setting of the stitch length described in the foregoingpassage, the pin 72 on the connecting bar 69 is held in the free driveportion 75 of'the slide lever 74. Consequently, no coupling takes placebetween the connecting bar 69 and the slide lever 74.

For the automatic control of the forward and reverse stitch the controlknob 32 and thereby disks 35 and 67 are rotated counterclockwise fromthe zero position in Fig. 5 causing the abutment 46, on the one hand, toenter the widening section of the aperture 36 and, on the other hand,causing an angular clockwise shift of the connecting bar 69 about itsaxis of rotation 71 as a result of the en trance of pin 68 on the disks35 and 67 into throat 70 of the connecting bar 69. In turn the pin 72 onthe connecting bar 69 is caused to enter slot 73 of the guide or slidelever 74 (Fig. 6), thereby coupling them together so that the guidingimpulses derived from the guide disk 88 are applied to the slide lever74 and thence to the stitch setting slide 17. The impulses applied tothe stitch setting slide 17 increase in magnitude as the pin 72 is movedfurther into the slot 73. This relationship is only maintained, however,with the arcuate slot 73 described hereinabove. By forming the slot 73differently or even by differently positioning the slide lever 74 inrelation to the pivot axis 71, it is possible by suitably shifting thepin 72 in the slot 73 to transfer the impulses derived from guide theembodiment illustrated in the drawings, We do not wish to be limitedthereto, but what we desire to protect by Letters Patent is set forth inthe appended claims.

We claim:

1. Stitch adjusting mechanism for a sewing machine having an arm shaft,a stitch setting cam and a dog raising cam on said arm shaft, a feed dogadvancing shaft, a setting cam follower bar connecting said advancingshaft to said setting cam, a feed dog raising shaft, a raising camfollower bar connecting said dog raising shaft to said dog raising cam,a stitch guiding cam operatively geared to said arm shaft and a guidingcam follower pivotally mounted adjacent said guiding cam in operativeengagement therewith, a guided slide member pivotally connected to saidsetting cam follower bar and a stitch setting slide pivotally mounted inthe machine housing in engagement with said slide member; said mechanismincluding an abutment lever pivotally mounted at one end on a support inthe machine housing and connected at the other end to a draw bar linkedto said stitch setting slide and presenting an abutment pin, a guidelever pivotally mounted for movement with said abutment lever having aguiding portion and a free motion portion, a stitch setting shaftrotatably mounted in the standard of the machine presenting an externaloperating knob, a guide disk secured to said stitch setting shaft havingan elongated aperture defining forward and reverse stitch guiding curvesfor engagement by said abutment pin, an impulse transmission barpivotally linked to said guiding cam follower having a stud and aslotted throat portion, said guide disk presenting a pin adapted uponrotation of said disk to enter said slotted throat portion and advancesaid stud into said guiding portion thereby coupling said impulsetransmission bar by way of said guide lever, said abutment lever andsaid connecting link to said stitch setting slide.

2. Stitch adjusting mechanism for a sewing machine having an arm shaft,a stitch setting cam and a dog raising cam on said arm shaft, :1 feeddog advancing shaft, a setting cam follower bar connecting saidadvancing shaft to said setting cam, a feed dog raising shaft, a raisingcam follower bar connecting said dog raising shaft to said dog raisingcam, a stitch guiding cam operatively geared to said arm shaft and aguiding cam follower pivotally mounted adjacent said guiding cam inoperative engagement therewith, a guided slide member pivotallyconnected to said setting cam follower bar and a stitch setting slidepivotally mounted in the machine housing in engagement with said slidemember; said mechanism including an abutment lever pivotally mounted atone end on a support in the machine housing and connected at the otherend to a draw bar linked to said stitch setting slide and presenting anabutment pin, a guide lever pivotally mounted for movement with saidabutment lever having a guiding portion and a free motion portion, astitch setting shaft rotatably mounted in the standard of the machinepresenting an external operating knob, a guide disk secured to saidstitch setting shaft having an elongated aperture defining forward andreverse stitch guiding curves for engagement by said abutment pin, animpulse'transmission bar pivotally linked to said guiding cam followerhaving a stud and .a slotted throat portion,

' said guide disk presenting a pin adapted upon rotation of cam 88proportionately for the control of the stitch length" of .the forwardand reverse stitches.

Having now described our invention with reference to said disk to entersaid slotted throat portion and advance said stud into said guidingportion thereby coupling said impulse transmission bar by way of saidguide lever, said abutment lever and said connecting link to said stitchsetting slide, and a spring biased reversing lever having an arm adaptedto engage a member on said abutment lever and operative to effectengagement of said stud with said reverse stitch setting curve, saidreversing lever being supported on a shaft extending through said stitchsetting shaft and presenting an exterior operating lever.

3. Stitch adjusting mechanism for a sewing machine having an arm shaft,a stitch setting cam and a dog 'raising cam on said arm shaft, a feeddog advancing shaft, a setting cam follower bar connecting saidadvancing shaft to said setting cam, a feed dog raising shaft, a raisingcam follower bar connecting said dog raising shaft to said dog raisingcam, a stitch guiding cam operatively geared to said arm shaft and aguiding cam follower pivotally mounted adjacent said guiding cam inoperative engagement therewith, a guiding slide member pivotallyconnected to said setting cam follower bar and a stitch setting slidepivotally mounted in the machine housing in engagement with said slidemember; said mechanism including an abutment lever pivotally mounted atone end on a support in the machine housing and connected at the otherend to a draw bar linked to said stitch setting slide and presenting anabutment pin, a guide lever pivotally mounted for movement with saidabutment lever having a guiding portion and a free motion portion, astitch setting shaft rotatably mounted in the standard of the machinepresenting an external operating knob, a guide disk secured to saidstitch setting shaft having an elongated aperture defining forward andreverse stitch guiding curves for engagement by said abutment pin, animpulse transmission bar pivotally linked .to said guiding cam followerhaving a stud and a slotted throat portion, said guide disk presenting apin adapted upon rotation of said disk to enter said slotted throatportion and advance said stud into said guiding portion thereby couplingsaid impulse transmission bar by way of said guide lever, said abutmentlever and said connecting link to said stitch setting slide, and aspring biased reversing lever having an arm adapted to engage a memberon said abutment lever and operative to effect engagement of said studwith said reverse stitch setting curve, said reversing lever beingsupported on a shaft extending through said stitch setting shaft andpresenting an exterior operating lever, said guiding portion being inthe form of a slot extending longitudinally of said guide lever and saidfree motion portion being an aperture defined endwise of and extendingtransversely of said slot and permitting free movement of said stud andof said impulse transmission bar.

4. Stitch adjusting mechanism for a sewing machine having an arm shaft,a stitch setting cam and a dog raising cam on said arm shaft, a feed dogadvancing shaft, a setting cam follower bar connecting said advancingshaft to said setting cam, a feed dog raising shaft, a raising camfollower bar connecting said dog raising shaft to said dog raising cam,a stitch guiding cam operativcly geared to said arm shaft and a guidingcam follower pivotally mounted adjacent said guiding cam in operativeengagement therewith, a guided slide member pivotally connected to saidsetting cam follower bar and a stitch setting slide pivotally mounted inthe machine housing in engagement with said slide member; said mechanismincluding an abutment lever pivotally mounted at one end on a support inthe machine housing and connected at the other end to a draw bar linkedto said stitch setting slide and presenting an abutment pin, a guidelever pivotally mounted for movement with said abutment lever having aguiding portion and a free motion portion, a stitch setting shaftrotatably mounted in the standard of the machine presenting an externaloperating knob, a guide disk secured to said stitch setting shaft havingan elongated aperture defining forward and reverse stitch guiding curvesfor engagement by said abutment pin, an impulse transmission barpivotally linked to said guiding cam follower having a stud and aslotted throat portion, said guide disk presenting a pin adapted uponrotation of said disk to enter said slotted throat portion and advancesaid stud into said guiding portion thereby coupling said impulsetransmission bar by way of said guide lever, said abutment lever andsaid connecting link to said stitch setting slide and a spring biasedreversing lever having an arm adapted to engage a member on saidabutment lever and operative to effect engagement of said stud with saidreverse stitch setting curve, said reversing lever being supported on ashaft extending through said stitch setting shaft and presenting anexterior operating lever, said guiding portion being in the form of aslot extending longitudinally of said guide lever and said free motionportion being an aperture defined endwise of and extending transverselyof said slot and permitting free movement of said stud and of saidimpulse transmission, said slide member and said impulse transmissionbar being spring biased. 7

References Cited in the file of this patent UNITED STATES PATENTS1,611,372 Rader Dec. 21, 1926 2,685,266 Pagni Aug. 3, 1954 2,704,986Pagni Mar. 29, 1955 2,751,868 Schwab June 26, 1956 FOREIGN PATENTS27,985 Great Britain Dec. 19, 1907 756,403 Great Britain Sept. 9, 1956

